The advantage offered to the cultivator by this description of worm, is economy in the quantity of food. In ordinary seasons, 12 pounds of mulberry leaves will nourish as many worms as produce one pound of cocoons, which is a saving of one tenth the average weight required for the production of a similar quantity by common worms. On the other hand, this variety occupies five or six days longer in passing through their mutations, and before they begin to spin. One hundred of their cocoons weigh a pound, and one thousand and ninety-one of them will yield one pound of reeled silk: each cocoon, therefore, furnishes nearly 8 grains of silk, and the length of its thread is very nearly 1300 yards. This breed of worms is to be found in Friuli.*

The constitution of worms of this larger species, does not offer inducements for their adoption into more temperate climates; but the advantages offered by the smaller variety make them worthy of observation and experiment on the part of silk cultivators.

CHAP. III.

MODE OF REARING SILKWORMS IN CHINA.

Silkworms sometimes reared on Trees.-Produce inferior to that spun in Houses.-Mode of delaying the Hatching of Eggs.-Method of Hatching. -Situation of Rearing Rooms.-Number of Meals.-Necessity of preventing Damp.-Of preserving Cleanliness.-Space allotted to Worms. -Preparations for Spinning.-Collection of Cocoons.-Destruction of Chrysalides.-Buildings employed for rearing Silkworms in India.

BEFORE entering upon any description of the methods practised in Europe for rearing silkworms, it appears desirable to give a brief account of the means employed for that end in China. It will be seen, from this sketch, how superior, in many respects, were the arrangements of the Chinese cultivators; and that in departing from the course so long pursued by them, Europeans made choice of modes less rational and simple for attaining the desired result. The inquiries and experiments of later days have brought us back from the confused procedures, which so long imparted uncertainty, and so frequently led to disappointment, and have introduced, instead, judicious and methodical arrangements.

*Friuli silk is said to be more troublesome and wasteful in its manufacture than that of either France or Lombardy; an effect which may be owing to their breed of worms.

In those parts of the empire where the climate is favorable to the practice, and where alone, most probably, the silkworm is indigenous, it remains at liberty, feeding at pleasure on the leaves of its native mulberry tree, and going through all its mutations among the branches, uncontrolled by the hand and unassisted by the cares of man. So soon, however, as the silken balls have been constructed, they are appropriated by the universal usurper, who spares only the few required to reproduce their numbers, and thus to furnish him with successive harvests.*

This silk, the spontaneous offering of nature, is not, however, equal in fineness to that which is spun by worms under shelter, and whose progressions are influenced by careful tendance. Much attention is, therefore, bestowed by the Chinese in the artificial rearing of silkworms. One of their principal cares is to prevent the too early hatching of the eggs, to which the nature of the climate so strongly disposes them. The mode of insuring the requisite delay is, to cause the moth to deposit her eggs on large sheets of paper: these, immediately on their production, are suspended to a beam of the room, and the windows are opened to expose them to the air. In a few days the papers are taken down and rolled up loosely with the eggs withinside, in which form they are hung again during the remainder of the summer and through the autumn. Towards the end of the year they are immersed in cold water wherein a small portion of salt has been dissolved. In this state the eggs are left during two days; and on being taken from the salt and water are first hung to dry, and are then rolled up rather more tightly than before, each sheet of paper being thereafter inclosed in a separate earthen vessel. Some persons, who are exceedingly particular in their processes, use a ley made of mulberry tree ashes, and place the eggs likewise, during some minutes, on snow water, or otherwise on a mulberry tree exposed to snow or rain.

These processes appear efficacious for checking the hatching, until the expanding leaves of the mulberry tree give notice to the rearer of silkworms that he may take measures for bringing forth his brood. For this purpose the rolls of paper are taken from the earthen vessels, and are hung up towards the sun, the side to which the eggs adhere being turned from its rays, which are transmitted to them through the paper. In the evening the sheets are rolled closely up and

*Note W.
K

placed in a warm situation. The same proceeding is repeated on the following day, when the eggs assume a grayish color. On the evening of the third day, after a similar exposure, they are found to be of a much darker color, nearly approaching to black; and the following morning, on the paper being unrolled, they are seen covered with worms. In the higher latitudes the Chinese have recourse to the heat of stoves, to promote the simultaneous hatching of eggs.

The apartments in which the worms are kept stand in dry situations, in a pure atmosphere, and apart from all noise, which is thought to be annoying to the worms, and especially when they are young. The rooms are made very close, but adequate means of ventilation are provided: the doors open to the south. Each chamber is provided with nine or ten rows of frames, placed one above the other. On these frames rush hurdles are ranged, upon which the worms are fed through all their five ages. A uniform degree of heat is constantly preserved, either by means of stoves placed in the corners of the apartments, or by chafing-dishes which from time to time are carried up and down the room. Flame and smoke are always carefully avoided: cow-dung dried in the sun is preferred by the Chinese to all other kinds of fuel for this purpose.

The most unremitting attention is paid to the wants of the worms, which are fed during the night as well as the day. On the day of their being hatched they are furnished with forty meals, thirty are given in the second day, and fewer in and after the third day. The Chinese believe that the growth of silkworms is accelerated, and their success promoted, by the abundance of their food; and therefore, in cloudy and damp weather, when the insects are injuriously affected by the state of the atmosphere, their appetites are stimulated by a wisp of very dry straw being lighted and held over them, by means of which the cold and damp air is dissipated.

It is affirmed by these accurate observers, that the quicker the worm arrives at its maturity, the greater is the quantity of silk which it spins. They say, that if the worms become fully grown in twenty or twenty-five days, each drachm weight of eggs will produce twenty-five ounces of silk; that if their maturity be delayed to the twenty-eighth day, only twenty ounces are obtained; and that if thirty or forty days elapse between the hatching and the commencement of the cocoons, then only ten ounces are the result.

The Chinese are exceedingly careful in preserving the

nicest degree of cleanliness in their establishments for rearing silkworms; being fully aware of the great importance which attaches to that particular.

The worms, as they increase in growth, have gradually more space assigned to them; so that the full-grown caterpillars have four times the scope that is allotted to them when newly hatched, and sometimes even more.

When the insects are about to commence their spinning, mats are provided, in the centre of which a strip of rush, about an inch broad, is fixed, and extended in a spiral form, or in concentric circles, over the whole surface of the mat, leaving an area of about an inch broad between each circle. Here the worms fix themselves to spin; and it is found that these receptacles occasion less silk to be wasted by them in floss, than when more space is allotted wherein their first threads can be spun. At this time the whole room is carefully covered with mats, to exclude the outward air and the light, as it is believed that silkworms work more diligently in darkness.

In seven days from the commencement of the cocoons they are collected in heaps, those which are designed to continue the breed being first selected and set apart on hurdles, in a dry and airy situation. The next care is to destroy the vitality of the chrysalides in those balls which are to be reeled. The most approved method of performing this is to fill large earthen vessels with cocoons, in layers, throwing in one fortieth part of their weight of salt upon each layer, covering the whole with large dry leaves resembling those of the water-lily, and then closely stopping the mouths of the vessels. In reeling their silk, the Chinese separate the thick and dark from the long and glittering white cocoons, as the produce of the former is inferior.

In India, the climate admits of silkworms being reared in buildings resembling sheds rather than houses. They are composed of lattice-work, and their roofs are covered with thatch. The breadth of such buildings is usually fifteen feet, and their height eight feet; their length is regulated by the extent of accommodation required. In the centre of the apartment a path is left, of convenient width for the attendants to pass and repass in supplying the wants of their charge; and on either side are twelve tiers or stages, one above another, of open frame-work, or shallow boxes made of bamboo, in which the worms are placed. When ready to spin, each worm is individually transferred to a small cell formed with platted strips of bamboo,

CHAP. IV.

MODE OF REARING SILKWORMS IN EUROPE.

Great Degree of Carefulness required.-Absurdities formerly believed concerning Silkworms.-Choice of Eggs.-Modes of Hatching.-Use of StoveRooms.-Their Temperature.-Conveying of Worms to Rearing-House.— Necessity for Classing Worms according to their Ages.-Reverend Mr. Swayne's Apparatus.-Space allowed to Worms.-Mode of Feeding.Quantity of Leaves consumed.-Arbors for Spinning.-Necessity of Attention to minute points in Management.-Regulation of Temperature. -Silkworms will not spin in cold atmosphere.-Ventilation.-Effect of Noise. Electric Influence.-Conductors.

THE various operations of an establishment for the production of silk are, ordinarily, all begun and concluded in the course of a few weeks; yet they call for a considerable degree of attention on the part of its conductor, and can hardly be brought to a successful issue without the aid of experience. This is especially the case in Europe, where atmospheric changes are continually arising, which in various ways influence the tender silk-producing insect. One false step in management might be fatal, and one day's relaxation of the breeder's cares would suffice to bring all his previous labors to nothing.

The degree of skilfulness and care thus required for the successful rearing of silkworms upon any useful scale, cannot be adequately estimated by the experience of those persons in England, who, as a matter of curiosity or of amusement, have watched over a few hundred worms, and have wound off the silk which these have furnished, unassailed by accident or misfortune. It is very natural to suppose, that what is so easily practicable with a small number, offers little difficulty as an extensive employment. If, however, the English breeder considers the time, however short it may have appeared, and the labor, however unimportant in his estimation, bestowed on his inconsiderable brood, and thence calculates the greater labor which must attend upon the rearing of hundreds of thousands, or, perhaps, millions of insects, its insignificance will disappear. He may then naturally imagine, how great is the importance of abridging that labor, of economizing expense, and of providing in every way against accidents, which, if occurring to interrupt his amusement, would be merely vexatious, but upon the avoiding of which, under other circumstances, depend the subsistence and well-being of thousands.

Many treatises have appeared from time to time containing